No Pain, Just A Slight Sound In My Ear. Will A Simple OTC Decongestant Would Clear It Up ?

I went to a doctor 3 times. 1st I was diagnosed with an ear infection and got a prescription of amox. When I was done with it, my 2nd trip was a check up to see if I needed and more antibiotics . After the the amox I started hearing what seemed to be this panting sound in my ear. When I was there, he notice I had some fluids and just told me a simple OTC decongestant would clear it up. After 2 weeks I went back and told him that I started having the breathing sound in my ear again after I gotten over a slight cold, but he didn t find anything wrong with my ears this time, and told me it s probably more fluid from the cold I caught. There is so pain at all just the sound, and it goes away normally after I take a warm bath/shower when I take the decongestant. Is it still fluid build up in my ear; because I ve heard in some cases it can take up to nine months to fully drain out.